The latest debate between Hillary Clinton and Bernie Sanders featured an unlikely guest — the Republican former secretary of State Henry Kissinger, who defined the role of the modern national security adviser as he helped President Richard Nixon reach his signature foreign policy accomplishments in the late 1960s and early 1970s.

Sanders attacked Kissinger in the Thursday night debate as "one of the most destructive secretaries of State in history." Clinton countered that Kissinger's work in opening up the People's Republic of China to the United States was an enduring achievement and that Kissinger knows China, Chinese officials and overall policy better than most people in history.

As an aside in a debate to win the hearts of an increasingly liberal Democratic primary electorate, Sanders' criticism may have drawn support, but it continued the inflation of Kissinger's true role — much of which Kissinger himself created.

Kissinger, whose German-accented English gave him an air of Old World gravitas and a whiff of Dr. Strangelove, helped create the secretive system in which Nixon ran his foreign policy. He ran a secret back channel with the Soviet Union that led to a landmark nuclear arms deal with the Soviets in 1972. He met secretly with Chinese leaders in July 1971 and enabled Nixon's successful visit there the following year. And his secret talks with North Vietnam led to the end of the Vietnam War and to Kissinger winning the Nobel Peace Prize.

Those were all heady accomplishments, and Kissinger used his sweeping knowledge of world affairs and his supple wit to achieve them.

But it was not his vision that Kissinger implemented. It was that of his patron — Nixon, the 37th president, who was forced to resign from office in disgrace in August 1974. ...